An integral mirror type laser system which produces miltiline emissions simultaneously and which is adapted for use in optical data processing systems. In particular, in a first embodiment, a unitary positive column laser comprises two sections, the first section comprising a positive column helium-cadmium laser, the second section comprising a positive column helium-neon laser, the first and second sections being coaxially aligned and having different inner diameters. Simultaneous excitation in the two different sections provides optimum excitation for red laser light, produced by the helium-neon section and blue laser light produced by the helium-neon-cadmium section. The present system also allows separate cadmium vapor pressure control by separately controlling the vaporization temperature of the cadmium and also allows confinement of the cadmium vapor whereby the vapor does not contaminate one of the optical windows which confines the active laser medium. By proper selection of the optical cavity parameters, simultaneous red and blue laser oscillations can be obtained for application in any optical data processing system that requires a red and blue laser radiation source. In a second embodiment, the helium-cadmium section is replaced by with a helium-selenium section whereby the tandem laser system is capable of producing multiline laser radiation in the red, blue and green colors.
A helium-cadmium laser having high reflector mirror and output coupler mirror properties which favor lasing at 353.6 nm while inhibiting lasing at 325.0 nm. The preferred characteristics of the high reflector and/or output coupler mirrors include transmission at 325.0 nm greater than 10% and transmission at 353.6 nm less than 5%.
